MEANS AND METHOD FOR STACKING THIN SHEETS

Abstract: The present invention is for a method of stacking of thin sheets and a device for stacking of thin sheets according to the method. The sheets can be made from paper, plastic film or the like. The invention is primarily intended to be used in connection with print outs in computer centres delivering a continuous, rapid and lengthy flow of paper sheets. The paper is brought into the stacker on a conveyer (4) comprising a number of parallel bands arranged side by side, which are controlled by pulley wheels and supporting wheels (5, 6, 7, 8). The papers are delivered from the conveyer (4) in the slit between the paper stack (16) and a second conveyer (9) which also comprises a number of parallel bands arranged sidewise passing over pulley wheels (10 and 24). The paper stack is supported by several supports (14) each having a resilient supporting edge (17) towards the paper stack. The stacker can be turned and tilted around an axis (25) at right angle to the plane of the figure.

Description: P-4232 Means and method for stacking thin sheets The present invention concerns a method for stacking of thin sheets and a device for stacking of thin sheets according to the method. The sheets can be made from paper, plastic film or the like. The invention is primarily intended to be used in connection with print-outs in computer centres delivering a continuous, rapid and lengthy flow of paper sheets. At larger computer centres there is often an almost continuous production of print-outs. The printers used for this purpose have a great capacity and the speed of the paper can be up to 1 meter per second, corresponding to 4 - 6 sheets per second. The printed papers are collected in stacks for further handling. A suitable height of a stack is up to 200 mm, which means that each such stack contains more or less numerous sets of print-outs for different adressees. In order to facilitate the further handling those parts of the stack which are intended for a certain adressee should be put displaced relative to the adjacent parts of the stack. This is often done in connection with that the continuous sheet from the print-out is split up to separate sheets. In order to facilitate this handling, the print-outs often have a bar code, either on each separate sheet or on the first and possibly the last paper for an addressee, whereupon the continuous paper sheets can be controlled by impulses which are received directly from the printer or by optical reading of the bar codes. It is then important that there is no further displacement of the paper in relation to other papers. The invention will below be described more in detail with reference to the embodiment shown in the accompanying figure. The device shown in the figure has two stackers 2, 20 for collecting of separate sheets to stacks of suitable size. The papers arrive to the device on a conveyer 1 and are received in a paper switch 25 where the paper is directed using air. The paper directed upwards is carried on to the upper stacker 2 and papers directed downwards are brought to the lower stacker 20 by the conveyer 3. The two stackers are of identical design and function. The paper is brought into the stack on a conveyer 4 comprising a number of parallel bands arranged side by side, which are controlled by pulley wheels and supporting wheels 5, 6, 7, 8. The papers are delivered from the conveyer 4 in the slit between the paper stack 16 and a second conveyer 9 which also comprises a number of parallel bands arranged sidewise passing over pulley wheels 10 and 24. The paper stack is supported by several supports 14 each having a resilient support edge 17 towards the paper stack. The stacker can be turned and tilted around an axis 25 at right angle to the plane of the figure. A paper incoming to the stacker from the conveyer 1 passes the paper switch 25 and we now assume that it directs the paper towards the upper stacker 2. The paper is catched onto the conveyer bands 4 and leave these after passing under the pulley wheels 7. The paper is then directed at an angle inwards towards the paper stack 17 and is brought up so that it passes in between the stack and the conveyer bands 9. These bands pass over upper pulley wheels 11 and lower pulley wheels 24. The lower pulley wheels 24 are mounted onto a shaft which is mounted onto arms extending up to the shaft 10 through the centre of the upper pulley wheels 15. The lower pulley wheels 24 can swing freely in this suspension device and if the rear supports 14 are in a certain position the pulley wheels 24 move gradually when further paper is delivered to the stack. In connection with this movement a position switch 15 is affected by the pivoting arrangement of the pulley wheels 24. The supports 14 are arranged so that they can be displaced in a direction towards or away from the conveyer bands 9. This displacement arrangement is affected by the position switch 15 and as the paper stack increases the supports 14 are moved away from the driving arrangement in small steps of 1 - 2 mm. The papers brought into the apparatus on the conveyer 1 are to have the text on the upper side. In this way the papers in the stack will be placed in order with the first paper on top and the last paper on the bottom. The maximum size of the stack is decided by the maximum allowed distance between the conveyer bands 9 and the supports 14. The desired size of a completed stack can, however, be controlled by different criteria, e.g. by means of a counting device determining the number of sheets or by measuring the thickness or weight of the stack. The above mentioned bar codes can be used to control the stacking so that papers which belong together are not put into different stacks, but one stack is completed with the last paper for a certain addressee. When the last paper of a stack is directed to the correct stacker, the paper switch 25 is shifted, which in this case means that the papers are directed to the conveyer 3 and conveyed to the lower stacker 20 where the papers are collected as described for the upper stacker. When the last paper has been put into position in the stacker 2, this is turned around the shaft 25 into a position which in the figure is marked by a part of a stacker 2A. The forkshaped stopper 13, against which incoming papers knock, is pivotally suspended from a shaft 12 and drops down to a position under the upper part of the conveyer 9, so that the papers are no longer prevented from moving in a direction to the left in the figure. In connection with the tilting of the stacker its driving motor 18 is disconnected and the conveyer bands 9 are connected to the driving conveyer 22. The stack is then brought out until it is on the conveyer 22 in the position as shown in the figure. The stacker has then been emptied and is tilted back into its starting position, whereby also the supports 14 are brought back to a position adjacent to the conveyer bands 9 and the stacker is then ready to receive new papers. When the lower stacker 20 contains a completed stack this is delivered in the same way as described above to a conveyer 21. This conveyer is movable in a vertical direction and can be raised up to the position marked 21A and is then a part of a continuous conveyer comprising a first conveyer band 22, the movable conveyer 21 and a final delivery conveyer band 23. The transport of the stacks is controlled in such a way that the upper paper of one stack on the conveyer 23 is the paper following directly after the bottom paper in the preceding stack.

Claims: CLAIMS 1) Method by stacking of thin sheets of paper or plastic film, preferably of standard size from a processing machine, where the processing takes place on endless sheet and where the endless sheet is broken up into separate sheets in known manner, characterized therein, that the flow of sheets is periodically split into two different flows in a sheet conveyer switch, after which switch each flow is directed to a stacker, where the sheets are brought to the stack from the bottom thereof by means of a conveyer, whereby the flow is switched between flow paths depending upon the height of the stack or the number of sheets in the stack and after switching from one path to another, the stacker which is made free delivers its stack to a conveyer with the first paper of the stack on top and is then made ready to receive sheets. 2) Method according to claim 1, characterized therein, that the flow of stacks from each stacker is brought together to one conveyer. 3) Method according to claim 1, characterized therein, that each stack before it is deposited from the stacker and still o kept therein is tilted more than 90 . 4) Device for stacking of thin sheets, comprising one or more stackers (2, 20), in which a stack is built by adding sheets from the bottom of the stack, which stacker is arranged to be o tilted more than 90 around a shaft from a sheet receiving position to a stack delivering position.

Inventors: SIXTENSSON ROLAND, SIXTENSSON, ROLAND
Applicants: RATIONELLA MASKI INGF, SIXTENSSON ROLAND, INGENJOERSFIRMAN RATIONELLA MASKINER AB, SIXTENSSON, ROLAND
Application year: 1994
Main classification: B65H33
IPC codes: B65H29, B65H31